﻿The 
  Memoir 
  Series 
  

  

  of 
  

  

  The 
  Geological 
  Society 
  of 
  America 
  

  

  is 
  made 
  possible 
  

  

  through 
  the 
  bequest 
  of 
  

  

  Richard 
  Alexander 
  Fidlerton 
  Penrose, 
  Jr. 
  

  

  